How to Build a Low-Cost Greenhouse With PVC Pipes
Uplifting Living Standards of People
Here below are the steps on how to build a greenhouse with PVC. The choice of PVC piping material as used in electrical conduits and water pipes is specifically targeted to low income people in developing countries since the PVC materials are inexpensive and readily available there. A greenhouse is ideal for growing crops in those areas where people live and water is a scarce resource. With a greenhouse, one can grow crops such as peppers, aubergines, tomatoes, cucumbers, cabbage, spinach, kales, French beans, peas, herbs, etc, etc which should go along way in uplifting the living standards of the people as they can feed on the crops they have grown as well as sell the produce to other markets to earn some extra revenue.
Greenhouse Building Codes
Greenhouses can be setup just about anywhere only if your local building codes allow this. If your land title deed is classified as ‘residential’ or ‘commercial’, you will need to get permits from your local authority and environmental protection authority. If your land title deed is classified as ‘agricultural’, you do not need any permits and you are encouraged to go ahead and put up greenhouses for intensive production of your crops.
Define the Greenhouse That We Need
We first define what we need as follows:
1. A greenhouse that will withstand average wind speeds of 15 knots and winds that may gust all the way up to 50 knots.
2. A greenhouse that will withstand heavy rainfall of 50mm per hour
3. A greenhouse that is easy to build and will fit within a budget of $350
4. A greenhouse that for the most part will be built using locally available materials of PVC pipes which are cheap and readily available even in remote places of developing countries.
Greenhouses Made With PVC Pipes
PVC Electrical conduits and PVC pipes are usually produced commercially in maximum length of 20 feet which is equal to 6.1 metres. That is the maximum length of PVC pipes you will find in most hardware stores. For a greenhouse to be constructed from PVC pipes and be strong enough to withstand rough weather, and be most economical in terms of space, it should have a base width of 12 to 14 feet. We shall make ours to have a base width of 14 feet which is equal to 4.3 metres; – the base length of the PVC pipes’ greenhouse can be made as long as you may wish. The other thing is that the greenhouse should have a door tall enough for you to fit. Our greenhouse will have a door of 2.1 metre in height.
Base Width of the Greenhouse
We shall fold the PVC pipe so that it will curve upward like a half circle with a diameter of 4.3 metres. The diameter of 4.3 metres will be the length of the base width of our greenhouse. This PVC pipe arc will be supported by the frame of the door as shown in the diagram below.
Looking at the diagram above, the radius of the half-circle is 14/2 equals 7’ which is the hypotenuse of the triangle shown. The height of our door is 6.75’ (equals 2.1 metres) which is the height of the triangle shown. We want to calculate the base of that triangle using Pythagoras theorem.
The square of base = (2.15 x 2.15) – (2.1 x 2.1) = 4.62 – 4.41 = 0.21
Length of base of triangle = square root of 0.21 = 0.46
4.3 = (2 x Y) + (2 x 0.46)
Y = (4.3 – 0.92)/2
Y = 1.69 metres which is equivalent to 5.55 feet
Width of the door = 0.46 x 2 = 0.92 metres equals to 3.0 feet
Choosing a Ground Site
Get a ground site which is at least 14 feet in width and with a length of at least 20 feet. The length of your greenhouse should be determined by how long you want it to be. The site should be free from the shading of trees and buildings as they will obstruct the lights that go into the greenhouse. Make sure the site chosen allows for good drainage and it’s not mash or soggy. Prepare it as you would prepare a garden so that you do away with weeds as weeds can latter become a big problem in the greenhouse.
Marking the Ground
By use of a measuring tape and wooden sticks, mark the ground as shown in the diagram below.
Get Yourself Some Tools: A Hacksaw and a Crowbar
Once you have finished marking the ground, get yourself some tools namely a hacksaw for cutting timber (lumber) and PVC pipes, a crowbar for digging holes on the ground and a steel file or abrasive paper for which you will use to smooth the sharp cut ends of timber and PVC pipes. These sharp ends of timber and PVC pipes if not smoothed out can tear the greenhouse polythene sheet which is expensive.
Use Crowbar to Dig Deep Holes
By use of a crowbar, dig four 2 feet deep holes as shown and marked in the ‘ground markings’ drawing above. You should then have bought the following:
1. 4 pieces of 4”x 2” timber each with a length of 2.71 metres (allow an extra 0.2 metres for error which you can cut or dig more deeper if it's too much)
2. 2 pieces of 4” x 2” timber each with a length of 0.92 metres (allow an extra 0.1 metres for error which you can cut if it's too much)
Key Support to Entire Greenhouse Structure
Place the four pieces of timber in each of the four holes such that each is 2.1 metres above the ground. Take care to reduce that height by about 2” as you will be placing another timber bar with a thickness of 2” on top of the four timber posts. Put the soil back on the holes and make it firm so that the posts will be strong and firm. It is, however, important to ensure that the part of the timber that is dipping in the soil is treated with fungicides or used engine oil to protect it from being damaged by insects. Using 4” nails, fix a 0.92 metres long timber bar on top of the two posts on each of the front and back sides. By use of a hacksaw, cut the end of the post where the horizontal bar is fixed to the vertical post. Cut it from the outer side such that you will cut a wedge that is 1” deep and 1” wide as in B, shown in the diagram below. The cut part will be the support for the 1.5” thick Sch 40 PVC pipe. This will now be the door frame which will act as the key support to the entire structure of your greenhouse. Latter on, as you grow your crops in your greenhouse, you will find the two door frames very useful as support for strings that you may add for support to your crops inside the greenhouse.
Buying PVC Pipes for the Greenhouse
The roofing PVC pipes are 1.5” thick and 20 feet long. The spacing between one roofing arc pipe and the next is 3.5 feet. The length of our greenhouse is 20 feet. This means we need 7 pieces of 1.5” thick PVC each 20 feet long; so we need to buy the following.
1. 7 pieces of 1.5” thick PVC each 20 feet long.
2. Add 2 more pieces of 1.5” thick PVC each 20 feet long for the two horizontal lengths.
3. The two horizontal widths will need 2 pieces of 1.5” thick PVC each 14 feet long.
4. Buy 7 pieces of 1.5” thick PVC pipes each 3.5 feet for use at the top as shown by E and F in the greenhouse plan below
5. Buy one tube of PVC glue
6. Buy these items from your local hardware store that is dealing with PVC electrical conduits or PVC water pipes. Buy the PVC pipes that are gray in color. When you are in that PVC store, buy the PVC glue from there.
PVC pipes have connectors that are used in extending the pipes or in curving and connecting the PVC pipes round corners. The same are available in PVC conduits. When you are using 1.5” pipes, you connect the pipes using 2” PVC connectors. Check for the corresponding sizes for your pipes with your dealer.
Buying PVC Connectors and Ground Stakes
You will need to buy the following connectors and ground stakes:
- 4 pieces size 2” 3–way PVC connectors for the four corners as shown by C in the greenhouse plan shown below.
- Another 2 pieces size 2” 3-way PVC connectors for use in the two top ends as shown by F in the greenhouse plan shown below
- 5 pieces size 2” 4-way PVC connectors for the 5 top connections as shown by E in the greenhouse plan shown below. You can substitute each of the 4-way connectors with two T-connectors if the price is lower for the two.
- Buy 14 pieces 12” long ground stakes/ground anchor for holding the horizontal PVC pipes firmly on the ground, or you can improvise yours locally by using wood or timber. Below is an image of a ground anchor that you can have a look at to fabricate yours.
- 5. Buy 0.25 kilogrammes of assorted nails 1”, 2”, 4”, and 6”
Laying the Ground PVC Pipes and Stakes
Now, lay the ground pipes as illustrated in the diagram above and do not forget to include the appropriate PVC connectors at the right spacing. Then fix the ground stakes but give room for final adjustments once you are through with fixing the greenhouse’s roofing PVC pipes.
Fold the front PVC pipe as shown in the drawing and fix it to the 3-way connectors on the ground. By use of nails, fix the pipe in position G so that the pipe is firmly in place. And by use of a file, smooth the tops of the nails so that you do not have a sharp end that can cut the PVC polythene sheet that will be put on top. Repeat the same for all the other PVC pipes just as shown in the drawing. Perhaps you may need someone to help you here. Use your ingenuity wherever you can. Finally, you will have everything in place as shown in the diagram below.
Make Greenhouse Door and Windows
After this, you need to make the greenhouse door and greenhouse windows. You will need to buy cheap and thin timber size 0.25” thick by 2” wide that will fit the dimensions of the door which are 6.75’ x 3.0’. The total length of this timber should be (6.75 + 6.75 +3 +3) x 4 equal 78 feet since the door and window will need double timber, with the UV protected polythene sheet being placed in between.
Use UV Protected Polythene on Doors and Windows
Cut the timber to fit the size of the doors taking into consideration the thickness of the outer frames of the doors which we had fixed earlier on. Cut the UV protected polythene sheet equal to the size of the frames made, and superimpose the polythene sheet in between the two frames, and by use of small nails or screws join frames and UV protected polythene to make a door. Do the same for the windows. Fix the door to the greenhouse supporting posts/frame using small sized hinges. The door should be fixed on the front side of the opening. On the rear side, put two windows (one on top of the other) instead of putting a door on that side. Two windows will give you better flexibility in controlling the humidity and temperature inside your greenhouse.
Before you cover your greenhouse with the UV protected polyethylene, you need to have enough snap clamps. You will use snap clamps to attach the UV protected polyethylene to the PVC pipes. Below is a picture of a snap clamp. You need to buy about 100 pieces of these from your PVC hardware store or you can make your own. By using a short piece of a 1.5” pipe, just cut out horizontally about 1/3 of the 1.5” PVC pipe and the remaining 2/3 part of the pipe can be used to attach UV protected polyethylene on 1.5” PVC pipes. But you have to ensure the cut edges are smoothed to remove any sharp end that can tear the UV protected polyethylene. It is however recommended you buy better ones from the manufacturers rather than making your own which may not work well as you would want.
Buying UV Protected Polyethylene Sheets
To complete building your greenhouse, you need to cover it with a UV protected polyethylene sheet. There are those UV protected polyethylene sheets which are 4 mil and will last for 3 years. And there are those UV protected polyethylene sheets which are 6 mil and will last for 4 years. The 6 mil UV protected polyethylene sheets offer better value for money. Our greenhouse has a top surface area of 20’ x 20’ equal 400 square feet. We need to add an additional 30% to cover the front and rear sides, the size that will hold it to the ground and wastage. This means we need about 520 square feet of UV protected polyethylene sheets.
UV protected polyethylene sheets are usually sold in width of 24 feet and you are charged per one-foot length of the 24’ wide sheet. A sheet of 4 mil will cost about $2.5 per feet and a sheet of 6 mil will cost about $3.0 per feet. If we divide 520 by 24 we get 21 feet. This means we need to buy 21 feet length of the 24’ wide sheet of UV protected polyethylene for the size of our greenhouse. At the price of $3.0 per feet, we should be prepared to spend $63 on a UV protected polyethylene sheet for our greenhouse. You will buy UV protected polyethylene sheets from your local stores that are dealing with greenhouse, polythene, plastic and insulation supplies.
Laying the UV Protected Polyethylene Sheet on the Structure
When you attach the PVC pipes with connectors, you do not use the PVC glue. This is because you want your greenhouse to be easy to dismantle as you may in future need to move your greenhouse to another site. The PVC glue is hardly used here, only in a few instances where you may fall short of a PVC pipe length and you may need to extend the pipe with an additional short pipe. Lay the UV protected polyethylene sheet appropriately to the structure you have built and attach it firmly to the pipes using snap clamps. Your ingenuity and flexibility are called upon here. The UV protected polyethylene should be firmly straightened up without leaving sinks that can hold water (or snow) when it rains. And finally, you have your UV protected polyethylene in place. Leave about 2 feet of the excess UV protected polyethylene covering on the ground which should be covered with soil or bricks to secure your greenhouse in place. This should be done after you have done the final tightening of the ground anchors.
Recapping What You Need to Buy to Construct a Greenhouse for Low Income People
We now recap what you need to buy to construct a Greenhouse. The prices indicated are approximate based on living standards in developing countries.
Unit $ price
Total $ Amount
4"x 2" timber each at a length of 2.71 metres @ $1/metre
4" x 2" timber each at a length of 0.92 metres @ $1/metre
1/4" x 2" timber each at length of 2.71 metres @ $ 0.1/metre
1/4" x 2" timber each at length of 0.92 metres @ $ 0.1
1.5" thick PVC pipes each 20 feet @ $ 0.2/feet
1.5" thick PVC pipes each 14 feet long @ $ 0.2/feet
1.5" thick PVC pipes each 3.5 feet long @ $ 0.2/feet
tube of PVC glue @ $4.0
2" 3-way PVC connectors
2" 4-way crosses PVC connectors
2" T-way PVC connectors
12" long plastic ground stakes/ground anchor
1/4 kilogrammes of assorted nails
1.5" Snap Clamp 4 inch long for 1-1/2" PVC pipes
24' wide 6 mil UV protected polyethylene @ $3.0 per feet
Total cost of materials
A Greenhouse for $253.90
The materials to build the 14 feet by 20 feet Greenhouse amounts to $253.90. This cost can be reduced by making some of the items yourself. Things such as snap clamps and ground stakes/ground anchors can be made from waste materials which you may get free from your backyard or whatever. Investing $253 for a greenhouse for low-income people in semi-arid and dry areas is worth the prices as they can be able to feed themselves and their families, as well as creating an income from selling the products produced from their greenhouses.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.